Battery Energy State Estimation via Lookup Tables

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Solution Overview

Problem

Traditional battery state of charge indicators do not accurately account for internal resistance losses, leading to a distorted representation of the actual energy available, especially in batteries with high internal resistance.

Innovation Solution

A method for estimating the final energy state of an electrochemical accumulator using a set of quadruplets of values related to operating points, including power, temperature, energy state, and remaining energy, through measurement, interpolation, and calculation of initial and final remaining energy, to provide a more accurate representation of the battery's energy availability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional state of charge indicator based on integral calculation of current is used, then the measurement is simple to implement, but the accuracy of energy state representation deteriorates due to not accounting for internal resistance losses

Engineering Contradiction:
Improveease of implementationVSAvoidaccuracy of energy state
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transforms the single-parameter SOC indicator into a multi-parameter energy state model (SOE, P, En, T) that accounts for internal resistance losses. By changing from a simple integral calculation to a comprehensive model incorporating power, temperature, and remaining energy, the accuracy of energy state representation is improved while maintaining computational feasibility through pre-calculated lookup tables and linear interpolation.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If comprehensive energy state model with multiple parameters is used, then the accuracy of energy state estimation is improved, but the computational complexity increases

Engineering Contradiction:
Improveaccuracy of energy stateVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary calculations during the battery's lifecycle testing to build comprehensive lookup tables containing quadruplets of (SOE, P, En, T) values. These pre-calculated tables are stored in memory and can be quickly queried during real-time operation. This preliminary action transfers computational burden from runtime to offline preparation, enabling accurate multi-parameter energy state estimation without excessive computational complexity during actual battery operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces pre-calculated lookup tables as an intermediary between the complex physical battery model and the real-time estimation system. Instead of directly solving complex differential equations during operation, the system uses the lookup tables with linear interpolation to achieve accurate energy state estimation with minimal computational resources. This intermediary structure decouples model complexity from computational requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If real-time energy state estimation with multiple parameters is implemented, then the representativeness of energy state is improved, but the processing time increases

Engineering Contradiction:
Improverepresentativeness of energy stateVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-calculates and stores comprehensive energy state data in lookup tables during offline battery characterization. This preliminary action enables real-time systems to quickly query pre-computed results rather than performing complex calculations during time-critical operations. The lookup tables contain pre-processed relationships between SOE, power, remaining energy, and temperature, allowing rapid estimation through simple interpolation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a simplified computational copy of the complex battery physics through lookup tables. Instead of replicating the full physical model in real-time calculations, the system uses tabulated data that captures the essential relationships. This copying approach preserves the accuracy of the comprehensive model while enabling fast real-time queries through memory access and linear interpolation rather than iterative numerical solutions.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2856188B1Method for determining a power status of an electrochemical battery; device; medium; and computer program
Publication Date: 2019.05.01 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2856188B1 patent drawingFigure 1~2
  • EP2856188B1 patent drawingFigure 3~5
  • EP2856188B1 patent drawingFigure 6~7

AI summary

The invention relates to a method for estimating a final power status SOEf of an electrochemical battery that is carried out on the basis of a set of quadruplets of values related to operational points of the electrochemical battery including power (P), temperature (T), power status (SOE), and the remaining power (En). Said method implements at least one interpolation step.